The purpose of a bearing protector is to prevent the ingress of fluid, solids and/or debris from entering a bearing chamber. Equally, bearing protectors are employed to prevent the egress of fluid or solids from a bearing chamber. Essentially, their purpose is to prevent the premature failure of the bearing.
Bearing protectors generally fall into two main categories: contacting or non-contacting.
Non-contacting bearing protectors can be of repeller or labyrinth configuration. Reference is made to our co-pending labyrinth seal bearing protection application GB0415548.7 which defines a substantially non-contacting bearing protector with static shut off device.
In a non-contacting bearing protector, the rotating component typically has a complex outer profile which is located adjacent and in close radial and axial proximity to a complex inner profile of the stationary component. Together these complex profiles, in theory, provide a tortuous path preventing the passage of the unwanted materials or fluids.
Conventional labyrinth seal technology indicates the said close radial counter rotational members are substantially parallel to each other and run parallel to the centreline of the shaft. Unfortunately, labyrinth seal technology has limited effectiveness at discouraging fluid, specifically in applications such as Pillow Blocks where angular displacement is expected between the shaft and the housing.
Contacting bearing protectors can be as basic as a lip seal, or more technical such as a face/mechanical seal. Reference is also made to our co-pending mechanical seal bearing protection application GB0215750.1, which defines a substantially contacting bearing protector with an axially floating seal face against axially static seal face.
Conventional mechanical seal technology suggests that the counter rotational seal faces attached to the rotor and stator need to be both flat, substantially parallel to each other, and substantially perpendicular to the shaft axis.
Again, unfortunately, said substantially parallel and perpendicular surfaces have limited effectiveness at sealing fluid, in applications such as Pillow Blocks where angular displacement is expected between the shaft and the housing.
Pillow Blocks are commonly employed in all types of industries, as they have the advantage of being able to accommodate angular misalignment of the installed equipment. Pillow blocks typically contain one or more centrally disposed bearings contained within a split housing. Two or more said bearing(s) and Pillow Block assemblies are employed to support a longitudinal and substantially rotatable shaft. It is preferable, that the bearing is lubricated during operation, therefore a seal is required, at either side of each split Pillow Block housing, to seal the bearing lubricant. As the two Pillow Blocks are axially spaced, the respective radial distance between the two can often vary from the ideal alignment. It is this radial distance variation that results in a shaft misalignment situation.
It is therefore deemed advantageous if a mechanism is created which permits both contacting and non-contacting bearing protector types to accommodate angular shaft to housing misalignment whilst permitting the effective sealing of the bearing lubricant fluid.
Several attempts have made to satisfy this basic sealing requirement, from Schickling U.S. Pat. No. 3,971,565, Lampart U.S. Pat. No. 5,655,845 and Orlowski, U.S. Pat. No. 5,335,921 and WO 98/02669.
Orlowski U.S. Pat. No. 5,335,921, teaches a two elastomeric members located either side of a projection from a carrier, and frictionally fitted to the sides of the split pillar block. Orlowski relies on the relative elasticity of said elastomer members to accommodate angular misalignment between the carrier and pillar block housing.
Orlowski, further uses frictional wear rings connected from the carrier to the shaft to force the stationary carrier to align to the rotating shaft.
The experience reader should note several technical drawbacks with Orlowski U.S. Pat. No. 5,335,921, as follows;                the frictional rings wear between the rotating shaft and stationary carrier. The worn particles dispersed adjacent and into the sealed bearing lubrication fluid. Said contaminates deteriorate the lubrication media leading to premature bearing failure.        as the elastomeric members are resiliently mounted between the carrier and pillar block housing when the equipment is aligned, given a misalignment situation, one of the two elastomeric members will compress over part of its circumference, whilst the compression on the second elastomer is relieved over part of its circumference. Likewise, the compressive forces at the other part of both elastomers circumferences changes. This irregular circumferential compression force is transmitted through to the frictional rings, accelerating the wear.        all frictional contacting members positioned between two counter rotating surfaces wear both the member and often the surface of the rotor/stator. Such frictional rings thus wear grooves in the shaft, leading to expensive equipment refurbishment costs.        the equipment shaft to housing is angularly rotated about the centreline of the bearing. Often double spherical roller/ball bearings are employed in spilt pillar blocks. Said spherical roller bearings angularly rotate about the radius of the bearing race. Any sealing member which does not also rotate about this bearing race radius is thus resisting the angular rotation, leading to further wear, rapid deterioration of both the bearing and the equipment and failure of the equipment.        
It is thus deemed to be further advantageous if said angularly accommodating mechanism, adjacent to the sealing member, does not angularly conflict with the natural angular movement of the bearing.
Furthermore, it is deemed to be advantageous to avoid the use of frictional alignment wear rings particularly adjacent to the sealed bearing lubricant fluid and not to create uneven circumferential forces around the seal member in a misaligned equipment configuration.